It was written, prosecutors say, in a red notebook. A string of entries, scribbled over months, that allegedly laid out the logic, the justification, and finally—the execution—of a murder meant to be a message.
On Wednesday, state prosecutors submitted new evidence in the case against Luigi Mangione, the 27-year-old accused of killing UnitedHealthcare CEO Brian Thompson in December. Among the filings: what they claim is Mangione’s personal diary, recovered during his arrest in Pennsylvania after a five-day manhunt. Inside are what authorities describe as “manifesto-style” writings detailing his alleged premeditation—and ideology.
“So say you want to rebel against the deadly, greed fueled health insurance cartel,” Mangione allegedly wrote last August. “Do you bomb the HQ? No. Bombs = terrorism.”
Instead, prosecutors claim, Mangione turned to something more “targeted, precise.” He allegedly penned a chilling line in October:
“Wack [sic] the CEO at the annual parasitic bean-counter convention.”
Prosecutors Say Luigi Mangione Framed a Murder as a Message
Thompson, 50, was shot and killed outside the New York Hilton in Midtown Manhattan hours before he was scheduled to speak at a UnitedHealth investor conference. The gunman fled on a bike into Central Park. Five days later, a McDonald’s worker in Altoona, Pennsylvania, recognized Mangione from police bulletins. He was arrested wearing a mask—and allegedly in possession of the now-infamous red notebook.
According to prosecutors, the notebook not only shows planning, but also an intent to make Thompson’s killing a symbolic act. Mangione allegedly fixated on how a murder would land in the media:
“The point is made in the news headline: ‘Insurance CEO killed at annual investors conference.’”
That line, they argue, transforms the case from a targeted killing to a political one—and justifies the terrorism enhancement attached to Mangione’s charges.
See also: Luigi Mangione’s Defense Claims Unlawful Search During His Arrest
Echoes of Extremism
Among the writings, Mangione allegedly praises parts of the Unabomber’s ideology. One entry reads:
“Normies categorize him as an insane serial killer … and dismiss his ideas.”
In another, allegedly addressed “to the feds” and written while in custody, Mangione offers what reads like a grim apology:
“I do apologize for any strife or trauma, but it had to be done. Frankly, these parasites simply had it coming.”
Prosecutors claim these entries are more than just abstract musings—they’re motive.
“Open and Shut”?
In the new filing, Assistant District Attorney Joel Seidemann described the case against Mangione as “overwhelming.”
“If ever there were an open and shut case pointing to the defendant’s guilt, this case is that case.”
But Mangione has pleaded not guilty to both state and federal charges, which include first-degree murder, terrorism, weapons violations, and a firearm-related murder charge from the DOJ. His attorney has filed a motion to dismiss the state case entirely.
Federal prosecutors, with backing from Attorney General Pam Bondi, have said they intend to seek the death penalty.
See also: Luigi Mangione’s Lawyers Push to Get New York Charges Dropped
A Killer or a Symbol?
Despite the prosecution’s confidence, the case against Luigi Mangione has struck a nerve far beyond the courtroom. At nearly every hearing, the crowd outside the courthouse isn’t calling for justice for Brian Thompson—they’re chanting against the healthcare industry.
To some, Mangione isn’t just a defendant. He’s a symbol of rage against a system that bankrupts cancer patients, denies life-saving treatments, and posts record profits while people die on hold. His legal defense fund has raised over $1 million, and supporters describe him not as a monster, but as someone who “snapped for the right reasons.”
Online, the reactions split: some see a vigilante who lost his grip, others a terrorist exploiting real suffering. But to prosecutors, intent is intent. The goal was to send a message, and in their eyes, the alleged violence was too loud to ignore.
What’s Next
Mangione’s next court date on state charges is set for June 26 in Manhattan. In the meantime, prosecutors continue to frame the case not just as a high-profile murder—but as a calculated assassination with ideological roots.
Whether a jury will accept that interpretation—or whether the diary will even be deemed admissible—remains to be seen. But the picture emerging from these pages, alleged or not, is one of a man who believed violence could speak for him.
See also: Supporters Rally as Luigi Mangione Appears in Court
